Tectonics and Seismicity of the Yarlung Tsangpo Grand Canyon Region     

Shao Cuiru  You Huichuan  Cao Zhongquan  Wang Chunyong  Tang Fangtou  Zhang Decheng  Lou Hai  Xu Guangyin  Yang Qiyan  Mei Tuo  Xie Ping  Yu Gang 《中国地震研究》2009,23(2):144-160

The Yarlung Tsangpo Grand Canyon region is located in the frontal zone of the eastern Himalayan syntaxis, where neo-tectonics and seismicity are intensive and closely related to each other. In the region, two sets of fault structures have developed, striking NNE-NE and NWW-NW, respectively. Investigation shows that they differ markedly in terms of scope, property, active times and intensity. The NWW-NW trending faults are large in size, and most are thrust and thrust strike-slip faults, formed in earlier times. The NEE-NE-strike faults are relatively small in size individually, with concentrated distribution, constituting the NNE-trending shear extensional fault zone, which is relatively younger with evident late Quaternary activities. Strong earthquakes occur mainly in the areas or zones of intensive differential movement of the Himalayas, e.g. along the deep and large fault zones around the crustal blocks. Most earthquakes of M≥7.0 are closely related to tectonics, where large-scale Holocene active faults are distributed with complicated fault geometry, or the faults of multiple directions intersect. Among them, earthquakes of M≥7.5 have occurred on the NW and NE-trending faults with a greater strike-slip component in the fault tectonic zones.  相似文献   

A new Late Miocene chondrichthyan assemblage from the Chagres Formation,Panama     

《Journal of South American Earth Sciences》2015

The lLate Miocene Chagres Formation from northern Panama contains the youngest outcrops of the Panama Canal Basin. Here we report two chondrichthyan assemblages that include 30 taxa from both the Rio Indio and Chagres Sandstone Members of the Chagres Formation. We report 18 new fossil records for Panama and four for tropical America, constituting the most diverse chondrichthyan association for the Cenozoic of Panama. We performed a paleobathymetry analysis based on the modern water depth preference of extant chondrichthyan taxa. The assemblage from the Rio Indio Member is characterized by taxa with neritic affinities, suggesting depths <100 m, whereas the assemblage from the Chagres Sandstone Member is dominated by taxa with oceanic affinities, suggesting 200–300 m water depths. The Chagres Sandstone Member could have accumulated at the edge of a platform–upper slope, bordered by a deep oceanic margin.  相似文献   

空间信息技术在大运河保护规划中的应用探讨     

周文生  王敬国  毛锋  江慧 《测绘软科学研究》2010,(3):40-44,78

大运河保护规划的编制是实施大运河整体保护的重要手段,也是推进大运河保护与申遗工作的关键。本文针对大运河保护规划所面临的问题探讨了空间信息技术应用于大运河保护规划编制的业务模型,在此基础上对大运河保护规划辅助支持系统的体系结构、功能模型以及保护规划数据库进行分析与设计,最后,对该系统的实现以及应用情况进行了介绍。实践表明,基于空间信息技术所构建的大运河保护规划支持平台可在大运河保护规划的各个阶段发挥重要的作用,并可使大运河保护规划编制效率与规划成果的科学性大大加强。  相似文献   

Analysis of historical data for a better understanding of post-construction landslides at an artificial waterway     

Annika Wohlers  Bodo Damm 《地球表面变化过程与地形》2021,46(2):344-356

With growing urbanization, an increasing number of landslides worldwide are linked to construction works, especially along transportation routes. To get a better understanding of these post-construction landslides at artificial waterways, archive studies have been conducted, in addition to analysis of historical scientific literature and technical reports. The resultant database is used to describe the occurrence and the characteristics of the landslides at the Mittelland Canal, and to evaluate aspects of conditioning and preparatory factors, potential triggers and applied mitigation measures. The Mittelland Canal has been chosen because it is one of the most important artificial waterways in Europe, and the high number of landslides that occur there is unique. In particular, landslides at the Mittelland Canal were frequently reported in the first half of the 20^th century. The susceptibility to landslides is strongly influenced by material characteristics, as a large number of landslides is linked to sites where fine-grained mudstone is abundant, which quickly decomposes under immersion in water or under dynamic stress. In addition, landslides can be linked to the creation of over-steepened slopes. Construction works can also be considered another preparatory factor for landslides. In addition, some landslides in World War II appear to be connected to the blast of aerial bombings. Precipitation seems to play a minor role in triggering landslides. The applied mitigation measures were developed recently, marking the importance of the canal as a transportation route. © 2020 John Wiley & Sons, Ltd.  相似文献   

EDITING NATURE IN GRAND CANYON NATIONAL PARK POSTCARDS*     

YOLONDA YOUNGS 《Geographical review》2012,102(4):486-509

This research takes a critical look at the interplay of vision and the production of knowledge in the context of cultural constructions of nature and environmental perceptions. The basis for this work is an exploration of the manufacturing process and subject matter in 259 Curt Teich Company postcards of Grand Canyon National Park manufactured from 1936 to 1955. Through a content analysis and interpretation of the postcards, four themes emerge—scenery, vegetation, water, and animals—that reveal the structure of Curt Teich Publishing Company's representation of the Grand Canyon environment. The company employed a printing technique known as “color embellishment” that allowed the manufacturer to alter the postcards with each reprinting and, in the process, create an edited view of nature at the Grand Canyon. This visual shorthand equated a series of selective and repetitive subjects and locations with ideas of scenic, wild, and grand landscapes.  相似文献   

红旗渠·林虑山地质公园景观特征及旅游体系研究     

张吉献  田广增 《城市地质》2010,5(4):25-29

红旗渠·林虑山国家地质公园的地质遗迹是华北地区地质演化的缩影,是一座天然的沉积构造陈列馆和教科书。公园不仅有壮观的地质工程——红旗渠,还具有＂雄、奇、险、秀、幽＂的美学特征,可以开展生态、体育和文化游。  相似文献   

ANALYSIS OF REMOTE SENSING ARCHAEOLOGY ON TRAFFIC FUNCTION TRANSFORMATION OF TONGJI GRAND CANAL IN SUI AND TANG DYNASTIES     

WANG Xin-yuan HE Hui ZHOU Ying-qiu GAO Chao HAN Shuang-wang 《中国地理科学(英文版)》2006,16(2):95-101

In China, most directions of river flowing are from west to east. During historic period, since the water traffic played an important role, it was very important to form a cross-horizontal net of water carriage route. Canals should be dug so as to make up the lack of north-south river. There was a far long history in Chinese canal de- velopment. From local north-south canal cutting in the Spring and Autumn Period and Warring States Period (770 B.C.- 222 B.C.), to primaryformation ofthe na…  相似文献   

第六次国际耦合模式比较计划（CMIP6）评述   总被引：4，自引：0，他引：4  

周天军  邹立维  陈晓龙 《气候变化研究进展》2019,15(5):445-456

世界气候研究计划（WCRP）发起了新一轮的国际耦合模式比较计划（CMIP6),目的是回答当前气候变化领域面临的新的科学问题,为实现WCRP“大挑战”计划所确立的科学目标提供数据支撑。文中回顾了CMIP的发展历程,介绍了CMIP6的组织思路,阐述了CMIP6核心试验及23个模式比较子计划（MIPs）的科学关注点,总结了参与CMIP6的全球模式概况以及中国的贡献。最后,从继承性和创新性等角度对CMIP6进行了评述,指出了CMIP6组织和实施中存在的问题,并对CMIP未来的发展进行了展望。  相似文献   

Magnetostratigraphy of Upper Cretaceous strata in Grand Staircase-Escalante National Monument,southern Utah: The Santonian–Campanian Stage boundary,reassessment of the C33N/C33R magnetochron boundary,and implications for regional sedimentation patterns within the Sevier Foreland Basin     

《Cretaceous Research》2016

Samples were collected for magnetostratigraphic analysis from the Upper Cretaceous Straight Cliffs and Wahweap formations within Grand Staircase-Escalante National Monument, southern Utah, in an attempt to locate the C34n–C33r and C33r–C33n boundaries; the former approximates the Santonian–Campanian Stage boundary. Locating both of these horizons within the Monument provides for refined temporal resolution of the many new fossil localities discovered in these units, while also adding to our understanding of the overall Straight Cliffs–Wahweap sequence stratigraphic architecture. Results indicate that the John Henry and Drip Tank members of the Straight Cliffs Formation are of normal polarity, and represent the later part of C34n, the Cretaceous Normal Polarity Super-Chron. The C34n–C33r boundary apparently resides in a significant hiatus determined to occur between the Drip Tank Member of the Straight Cliffs Formation and the lower part of the overlying Wahweap Formation. In stratigraphically ascending order, the informally named lower, middle, and most of the upper members of the Wahweap Formation are of reversed polarity. The C33r–C33n polarity change occurs in the upper part of the upper member, and C33n continues stratigraphically upward through the capping sand member of the Wahweap Formation and into the overlying Kaiparowits Formation. The presence of over 200 m of reversely magnetized strata above a level in the lower part of the middle member dated to 79.9 ± 0.3 Ma, which coincides with the GTS2012 date for the C33r–C33n boundary of 79.9 Ma, suggests that the published age of that boundary may be in error. A new date of approximately 78.91 Ma is proposed, in turn allowing for the thick sequence of reversely magnetized strata above the 79.9 Ma level. Age revision of the Kaiparowits Basin's Late Cretaceous record demonstrates that during late Santonian through early middle Campanian time, except in central Utah, a close correlation in time and facies successions with other successions throughout the Western Interior Basin suggests a eustatic influence on the depositional patterns. Starting in the late middle Campanian, the Kaiparowits record, along with those both to the north and south, appear to diverge in style and facies successions. We consider this to have resulted from a fundamental change in depositional controls triggered by the Laramide Orogeny. The anomalous central Utah record appears to have been profoundly influenced by a massive salient (Nebo-Charleston thrust system) in the Sevier Fold and Thrust belt that was active for much of the Late Cretaceous.  相似文献   

50,000 years of vegetation and climate history on the Colorado Plateau, Utah and Arizona, USA     

Larry L. Coats  Kenneth L. Cole 《Quaternary Research》2008,70(2):322-338

Sixty packrat middens were collected in Canyonlands and Grand Canyon National Parks, and these series include sites north of areas that produced previous detailed series from the Colorado Plateau. The exceptionally long time series obtained from each of three sites (> 48,000 ¹⁴C yr BP to present) include some of the oldest middens yet discovered. Most middens contain a typical late-Wisconsinan glaciation mixture of mesic and xeric taxa, evidence that plant species responded to climate change by range adjustments of elevational distribution based on individual criteria. Differences in elevational range from today for trees and shrubs ranged from no apparent change to as much as 1200 m difference. The oldest middens from Canyonlands NP, however, differ in containing strictly xeric assemblages, including middens incorporating needles of Arizona single-leaf pinyon, far north of its current distribution. Similar-aged middens from the eastern end of Grand Canyon NP contain plants more typical of glacial climates, but also contain fossils of one-seed juniper near its current northern limit in Arizona. Holocene middens reveal the development of modern vegetation assemblages on the Colorado Plateau, recording departures of mesic taxa from low elevation sites, and the arrival of modern dominant components much later.  相似文献